Method of making grids intended for use in electron discharge-tubes



Oct. 27, 1964 G. MOESKER 3,154,113

METHOD OF MAKING GRIDS INTENDED FOR use IN ELECTRON DISCHARGE-TUBESFiled April 8, 1958 INVENTOR GERARD MOESKER ME T United States Patent3,154,113 METHOD OF MAKING GRIDS INTENDED FOR USE IN ELECTRONDISCHARGE-TUBES Gerard Moesker, Eindhoven, Netherlands, assignor toNorth American Philips Company, Inc., New York,

N.Y., a corporation of Delaware Filed Apr. 8, 1958, Ser. No. 727,140Claims priority, application Netherlands Apr. 24, 1957 1 Claim. (Cl.14071.5)

The present invention concerns a method of making grids intended for usein electron-discharge tubes or the like, by winding wire on gridbackbones to form a grid subsequent to which the wire is cut apart orsevered in some other way and a next grid is wound after axialdisplacement of the grid backbones. This may be termed winding withoutwaste turns.

The aforesaid method is known (British patent specification 743,828).

It has now been found that this method permits, in a structurally easymanner, further important operations to be carried out on one and thesame machine so as to provide a fully automatic machine deliveringready-made grids.

The method according to the invention has the feature that, afterwinding a grid by means of pitch tongs gripping the backbones anddisplacing them in axial direction so as to wind with the desiredpitch(es), a second pair of tongs is made to co-act with theprovisionally closed first-mentioned tongs and with the grid backbonesso as to stretch them between both pairs of tongs, subsequent to whichthe first-mentioned pitch tongs are opened and moved back in axialdirection away from the grid backbones for the next winding operation,while the second pair of tongs (stretching tongs) are opened to permitthe passage of the grid backbones together with the grids for furtherprocessing. Exactly when using the method, in which the wire is eachtime severed and waste turns are avoided, time is available for alsoperforming a stretching operation on the machine, while using only twopairs of tongs.

In a further important development of the method according to theinvention, the grid backbones, after passing the stretching tongs, areperiodically cut apart to form individual grids which are temporarilysupported on a mandrel co-acting with members for deforming the grid,the mandrel being axially movable so that the deformed grid is strippedOE and removed.

The invention also has the advantage of permitting hotstretching. Inhot-stretching, however, there may occur undue oxidation of the gridbackbones and of the wire wound on them.

According to the invention, this oxidation can be undone on one and thesame machine.

In one embodiment of the invention, in which hotstretching occurs, thegrid backbones together with the wire wound on them is passed, betweenthe stretching tongs and the cutting members, through a chamber to whichreducing gas is supplied.

The machine for carrying out the method according to the inventioncomprises in known manner a device for feeding grid backbones, a windinghead for winding wire on the backbones and arranged for severing thewire periodically and rewinding it on the backbones, and tongs formoving the grid backbones in an axial direction.

Adjacent the first-mentioned tongs (pitch tongs) a second pair of tongs(stretching tongs) is provided, according to the invention, on the sideremote from the winding head, both pairs of tongs operating so as topermit the backbones to be stretched between them.

As a further development of the invention, namely "ice to perform asmany operations as possible on one and the same machine, one form of themachine according to the invention, which is arranged for heating thebackbones and the wire wound on them between the pitch tongs and thestretching tongs comprises a chamber supplied with a reducing gas andlocated between the stretching tongs and the cutting members, throughwhich chamher the grid backbones and the wire wound on them are passed.

In order that the invention may be readily carried into effect, anexample will now be described in detail with reference to theaccompanying drawing, in which FIG. 1 shows the main elements ofthemachine in plan view,

FIG. 2 is an elevational view on a larger scale according to the arrowII in FIG. 1,

FIGS. 3 and 4 illustrate the cutting operation,

FIG. 5 illustrates the shaping of the grid, also termed ondulation,

FIG. 6 is a schematic sectional view of the slides 10 and 14 illustratedin FIG. 1,

FIG. 7 is a detailed perspective view of a cutter mechanism foractuating cutters 44 and 45 illustrated in FIGS. 1, 3 and 4,

FIG. 8 is a detailed front elevational view of a mechanism for actuatingthe former 20 illustrated in FIGS. 1, 2 and 5, and

FIG. 9 is a detailed perspective view of a mechanism for actuating thestripping mandrel 25 illustrated in FIG. 1, left-hand side thereof.

In a driving gear case 1, a winding head 2 is pivotally supported arounda guide (not shown) for grid backbones- 3 and 4, which are unwound froma reel 5 and are superimposed, as shown in FIG. 3.

The construction of the winding head 2 is known per se (British patentspecification 743,828). By means of it turns of thin wire fed by thishead are wound on the backbones, preferably in notches of the backboneswhich are peened over later in order to secure the wire to thebackbones. In a manner also known per se a number of turns required fora grid is each time wound, subsequent to which the wire is cut apart orsevered in some other way and again wound on the backbones at somedistance from the preceding set of turns in order to form the next grid.

From the driving gear case 1 a shaft 6 projects, which has secured to ita cam 7 which, through a roller 8 and an arm 9, drives a slide 10comprising tongs 11 with jaws 11a and 11b adapted to be opened andclosed periodically. Roller 8, arm 9 and slide 10 may be constrainedagainst movement by a spring (not shown) which acts to return slide 10to the position shown in FIG. 1 and thus also maintain roller 8 incontact with cam 7. These tongs 11 are termed the pitch-tongs. They arecapable of gripping the backbones 3 and 4 and to impart to them alongitudinal movement, derived from the motion of the slide 10 and thecam 7, so that the wire turns obtain the required constant or variablepitch. The slide 10 is movable in a guide 12 and abuts against a stop13.

A further slide 14 is movable in the guide 12 and comprises tongs 15with jaws 15a and 1512 also capable of gripping the backbones 3 and 4.These tongs 15 are termed the stretching tongs.

The slide 14 is movable by the arm 16 against the action of a spring 17.The arm 16 may rest against an abutment stop 18.

A device known per se (not shown in the drawings) for burning olf wireends projecting beyond the backbones after attachment to the backbonesand severing the wire, is arranged near the Winding head 2 in the pathof the backbones 3, 4 carrying the wire turns.

In this path there is further disposed between the stretching tongs andthe pitch-tongs any suitable device 50 for temporarily passing currentthrough the backbones in order to heat them together with the wire woundon them. Next to the tongs 15, the path of the grid backbones comprisesa chamber 19 which is supplied with a reducing gas, for example mixedgas. The backbones 3, 4 carrying the turns are passed through thischamber, any oxidized spots resulting from the heat in hot-stretchingare subjected to reduction.

From the chamber 19, the backbones 3, 4 carrying the wire turns, at theleft in FIG. 1, are moved to a holder 20 containing shaping members 21,22, 23, 24 (see also FIGS. 2 and 5) adapted to give the grid the desiredshape (FIG. 5). This is effected in co-operation with a mandrel 25 whichis movable in a longitudinal direction, as indicated together with theholder 39, the gear wheel 40 co-acting, for example, with a toothed rack41 of the holder 39, and the tooth sector 43 driven by the shaft 42.

The holder 20 rotates about the shaping members 21, 22, 23, 24 andcontrols them with the aid of cams 31, 32, 35, 36 against the action ofsprings 33, 34 (FIG. 2). Arranged between the holder 20 and the chamber19 are knives 44, 45 (FIGS. 1, 3 and 4) each time cutting apart the gridbackbones 3, 4 between each two adjacent set of wire turns 46, 47, thebackbones 3, 4 being guided by the mandrel 25 and centered by theshaping members 21, 22 (FIG. 3).

The knives 44, 45 may be constructed and arranged so that the cuttingareas of the backbones are located slightly oifset in a longitudinaldirection thereof, which is desirable for some uses of grids.

The mandrel 25 co-acts with a stripping member 37. The reference numeral38 denotes a gutter through which the grids delivered by the machine arecarried off.

The operation is as follows:

At the beginning of winding a grid, the slide occupies the positionshown in FIG. 1. The tongs 11 are closed and move together with theslide 10 to the left in FIG. 1 according to a given pitch prescription.The tongs are open. After providing the number of turns required for agrid, the slide 10 abuts against a stop 13 or closely approaches it. Thetongs 11 provisionally remain closed and at the same time the tongs 15are closed. The latter together with the slide 14 are subsequently movedto the left in FIG. 1, subsequently, the grid backbones are stretchedbetween the tongs 11 and 15 with the slide 10 resting against the stop13.

The tongs 11 subsequently open and the slide 10 moves swiftly to theright, by virtue of a spring or other suitable known device, the tongs11 then being closed and the tongs 15 opened, the slide 14 being drawnby the spring 17 against the stop 18.

The grid backbones 3, 4 pass through the chamber 19 and are subsequentlycut, by any suitable mechanism such as illustrated in FIG. 7, thusforming individual grids, the grid cut free in this operation issupported on the mandrel 25 as illustrated in FIG. 3.

Each grid is subsequently ondulated by any suitable mechanism such asillustrated in FIGS. 2, 5 and 8, removed by means of the strippingmember 37 from the mandrel 25 and carried off into the gutter or tray38.

The common drive means for each of the various operations, i.e.cut-ting, ondulating and reciprocating mandrel 25, comprises the shaft59 and the various cams spaced therealong and driven thereby. Forpurposes of a simple design for the cutter mechanism, a separate shaft59a, parallel with and spaced from shaft 59, may be provided in aconvenient location as is Well known.

What is claimed is:

In a method of manufacturing grids for electron discharge tubes whereina grid wire is wound on continu ous backbones for a number of turnsbefore it is severed and the backbones displaced axially and anotherdiscrete number of turns of said grid wire is wound on said backbonesspaced from other discrete wire windings thereon; the methodcharacterized by applying a first gripping means to said backbones andmoving the backbones axially at a predetermined velocity to obtain adesired pitch and number of turns of said grid wire on said backbones,stopping said first gripping means, applying a second gripping means tosaid backbones spaced from said first gripping means at the opposite endof a discrete winding previously formed, moving said second grippingmeans for stretching the backbones between said first and secondgripping means, releasing the first gripping means and moving the secondgripping means and said backbones axially a predetermined distance Whilereturning the first gripping means to a starting position, releasingsaid second gripping means and applying said first gripping means atsaid starting position, returning said second gripping means to astarting position, supporting the wound and stretched backbones byaxially moving a mandrel means into supporting relation therewith,cutting said supported backbones between the discrete windings thereon,deforming the wound portion of said backbones while supported by saidmandrel means and thereafter retracting the mandrel means supporting thedeformed portion of the severed backbones to strip the mandrel means andrepeating the above enumerated sequence of steps to produce discretegrid winding on continuous straightened backbones.

References Cited in the file of this patent UNITED STATES PATENTS2,181,288 Washburn Nov. 28, 1939 2,197,533 Sutter Apr. 16, 19402,441,228 Schneider et al. May 11, 1948 2,727,540 Marshall et al. Dec.20, 1955 2,837,126 Hughes et al. June 3, 1958 2,995,156 Gartner et al.Aug. 8, 1961

